1. Click Start | Control Panel.
2. In the Control Panel, open the Network Connections applet.
3. In the Network Connections window (see
Figure A), open the New Connection Wizard.
Figure A
The Network Connections window
4. On the Welcome To The New Connection Wizard page, click Next.
5. On the Network Connection Type page (see Figure B), select the Set Up An Advanced Connection option.
Figure B 
On the Advanced Connection Options page (see
Figure C), select the Accept Incoming Connections option and click Next.
Figure C
Configuring XP to accept incoming connections
7.
On the Devices For Incoming Connections page (see Figure D), you can
select optional devices on which you want to accept incoming
connections.
Figure D
Note that you are not presented with any of the network interfaces on the computer.
8. On the Incoming Virtual Private Network (VPN) Connection page (see
Figure E), select the Allow Virtual Private Connections option and click Next.
Figure E 
9. On the User Permissions page (see
Figure F), select the users that are allowed to make incoming VPN connections. Click Next.
Figure F
Any user that isn’t selected won’t be able to initiate an incoming connection.
10. On the Networking Software page (see
Figure G), click on the Internet Protocol (TCP/IP) entry and click the Properties button.
Figure G
Configuring TCP/IP properties
11. In the Incoming TCP/IP Properties dialog box (see
Figure H),
place a check mark in the Allow Callers To Access My Local Area Network
check box. This will allow VPN callers to connect to other computers on
the LAN. If this check box isn’t selected, VPN callers will only be
able to connect to resources on the Windows XP VPN server itself. Click
OK to return to the Networking Software page and then click Next.
Figure H
Granting LAN access to callers
12. On the Completing The New Connection Wizard page, click Finish to create the connection.
After
the Incoming Connection is complete, right-click on the connection in
the Network Connections window and select the Properties command (see
Figure I).
Figure I
Accessing the properties of the VPN server link
When you place a VPN server behind your firewall, be sure to enable TCP port 1723.